Field of the Invention:
The present invention relates to an improvement of a seat structure of a valve adaptable to various kinds of valves such as butterfly valves, plate valves, etc.
Prior Art:
A seat ring to which a closure member contacts to close flow passage, hithertofore, was generally fixedly mounted to a valve body and unmovable when a flow pressure acted thereupon at a close position of a closure member.
There was also developed a seat ring which had a movable mechanism in a sealing direction under a flow pressure. The movability of a seat ring effected by a flow pressure can enhance the sealing effect attained by the close contact of a closure member with a seat ring.